Rotating prism component inspection system

ABSTRACT

An inspection system is provided. The system includes a rotating prism having a first end and a second end. The first end receives a first image area, such as a circular view, and rotates about a center point so as to cover a field of view area that is larger than the first image area, such as a larger circle that is defined by the smaller circle of view as it rotates around the center point. The second end remains centered on the center point and provides a viewing area that does not change in dimension. An image data system at the second end of the rotating prism generates image data as the prism rotates so as to generate two or more sets of image data that are contained within the field of view area.

BACKGROUND

Component inspection systems are known in the art. Such componentinspection systems use component image data to perform componentinspection. The component image data can be analyzed using a variety oftechniques to determine whether the component is acceptable orunacceptable.

One requirement for such component inspection systems is that the pixeldensity for image data that is used to inspect the component must have ahigh enough resolution to identify non-conforming conditions. Forexample, if a potential defect is one micron in diameter, then the pixelresolution must be less than one micron in order to generate image datahaving a sufficient resolution to identify and analyze the defect. Inorder to obtain a sufficient level of resolution, it is common to movethe camera or component that is being inspected, so as to cover two ormore sections of the component. However, moving the component or camerais time consuming, and slows the inspection process.

SUMMARY OF THE INVENTION

In accordance with the present invention, a system and method forcomponent inspection are provided that overcome known problems withcomponent inspection systems and methods.

In particular, a system and method for component inspection are providedthat use a rotating prism to provide a changing view to a camera, so asto allow the image data device to generate a higher resolution image ofthe component without the need for moving the camera or component.

In accordance with an exemplary embodiment of the present invention, asystem for inspecting a component is provided. The system includes arotating prism having a first end and a second end. The first endreceives a first image area, such as a circular view, and rotates abouta center point so as to cover a field of view area that is larger thanthe first image area, such as a larger circle that is defined by thesmaller circle of view as it rotates around the center point. The secondend remains centered on the center point and provides a viewing areathat does not change in dimension. An image data system at the secondend of the rotating prism generates image data as the prism rotates soas to generate two or more sets of image data that are contained withinthe field of view area.

The present invention provides many important technical advantages. Oneimportant technical advantage of the present invention is a system andmethod for inspecting components that utilizes a rotating prism or othersuitable devices to allow a component to be inspected by gathering anumber of image data sets, where each image data set is generated whenthe prism is at a different angular position. In this manner, multipledetail images of the component can be generated without moving thecomponent or camera.

Those skilled in the art will further appreciate the advantages andsuperior features of the invention together with other important aspectsthereof on reading the detailed description that follows in conjunctionwith the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a diagram of system for performing an inspection inaccordance with an exemplary embodiment of the present invention;

FIG. 1B is a diagram of a component in a field of view in accordancewith an exemplary embodiment of the present invention;

FIG. 1C is a diagram of a lens apparatus that is used to focus imagedata at viewing area;

FIG. 1D is a diagram of a light array disposed about a prism rotationsystem for a rotating prism;

FIG. 2 is a diagram of a system for inspecting components in accordancewith an exemplary embodiment of the present invention;

FIG. 3 is a diagram of system for quadrant data analysis in accordancewith an exemplary embodiment of the present invention;

FIG. 4 is a flowchart of a method for performing an inspection using arotating prism in accordance with an exemplary embodiment of the presentinvention; and

FIG. 5 is a flowchart of a method for inspecting components inaccordance with an exemplary embodiment of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

In the description that follows, like parts are marked throughout thespecification and drawings with the same reference numerals,respectively. The drawing figures might not be to scale, and certaincomponents can be shown in generalized or schematic form and identifiedby commercial designations in the interest of clarity and conciseness.

FIG. 1A is a diagram of system 100 for performing an inspection inaccordance with an exemplary embodiment of the present invention. System100 uses a rotating prism to generate image data over a field of viewthat is larger than a field of view of a camera, so as to allowcomponents to be inspected without moving the component or the camera.

System 100 includes rotating prism 102. Rotating prism 102 can be usedto transfer an image from an image area 104 to a viewing area 106. Thus,a viewer at viewing area 106 will see an image of what is containedwithin image area 104, where this image can change as rotating prism 102rotates. It is noted that a viewer at image area 104 would be able toobserve viewing area 106 through rotating prism 102, but that this viewwould only be that of a rotating viewing area 106. In this manner, afield of view can be encompassed at viewing area 106 by rotating prism102 that is larger than the field of view that can be directly coveredby viewing area 106 without the aid of rotating prism 102.

For example, image data system 110 can be used to directly generateimage data for component inspection or for other suitable purposes. Inthis exemplary embodiment, component inspection can be performed bydetermining the pixel density required to inspect features of thecomponent, such as by determining the area that must be covered by eachpixel in order to provide the required level of detail for recognitionof damage or other conditions. If the number of pixels required toinspect an entire component is greater than the number of pixelsgenerated by image data system 110 at the desired level of detail, itwould be necessary to move the component or image data system 110 inorder to generate image data of the entire component. Rotating prism 102can be used to provide the image data of the entire component to imagedata system 110 without moving either image data system 110 or thecomponent. In this manner, rotating prism 102 is rotated about an axissuch that viewing area 106 remains in the field of view of image datasystem 110 but image area 104 rotates around and covers an area or fieldof view that encompasses the entire component.

Rotating prism 102 includes prism rotation system 108. Prism rotationsystem 108 can be disposed about rotating prism 102, can be the devicethat holds rotating prism 102, can include motors or other motivedevices, lighting elements, and other suitable components. Prismrotation system 108 is coupled to quadrant inspection system 112, whichis also coupled to image data system 110. Quadrant inspection system 112and image data system 110 can be implemented in hardware, software, or asuitable combination of hardware and software, and can be one or moresoftware systems operating on a general purpose processing platform. Asused herein, a hardware system can include discrete semiconductordevices, an application-specific integrated circuit, a fieldprogrammable gate array or other suitable devices. A software system caninclude one or more objects, agents, threads, lines of code,subroutines, separate software applications, user-readable (source)code, machine-readable (object) code, two or more lines of code in twoor more corresponding software applications, databases, or othersuitable software architectures. In one exemplary embodiment, a softwaresystem can include one or more lines of code in a general purposesoftware application, such as an operating system, and one or more linesof code in a specific purpose software application. As used herein, theterm “couple” and its cognate terms, such as “couples” and “coupled,”can include a physical connection (such as a copper conductor), avirtual connection (such as through randomly assigned memory locationsof a data memory device), a logical connection (such as through logicalgates of a semiconducting device), other suitable connections, or asuitable combination of such connections. In one exemplary embodiment,systems and components are coupled to other systems and componentsthrough intervening systems and components, such as through an operatingsystem.

Image data system 110 generates image data for an area that correspondsto viewing area 106. In one exemplary embodiment, image data system 110can include one or more lenses, picture element (pixel) arrays, andother suitable image data generation components. For example, image datasystem 110 can generate a 1024×1024 pixel array or suitable arrays forcapturing the image presented in viewing area 106.

Quadrant inspection system 112 controls the generation of image data byimage data system 110 and the rotation speed of prism rotation system108. In this manner, image data system 110 can be used to capture imagedata from a suitable number of areas that encompass the entire componentbeing inspected. Depending on the field of view and the image area 104,one or more components could be inspected using system 100, such aswhere a first component is encompassed by the first half of the field ofview, and a second component is encompassed by a second half of thefield of view, where a component lies within each quadrant of the fieldof view, or in other suitable configurations.

Quadrant inspection system 112 can also accommodate for the angulardisplacement of image data generated by image data system 110. Forexample, features in the image data generated when rotating prism 102 isin a first position may have an angular displacement relative tofeatures in image data that is generated when rotating prism 102 is asecond position. If rotating prism 102 is generating image data ofquadrants of a die having straight rows of features that are beinginspected, then the angular orientation of the features in the firstquadrant image data can be 90 degrees displaced from the angularorientation of the features in the second quadrant image data. Quadrantinspection system 112 can rotate the image data, rotate the analysisframe, or otherwise compensate for changes in the angular orientation ofdata sets, so as to allow inspection of image data from differentsections of the field of view to be performed irrespective of theangular orientation of features in such sections relative to features inother sections.

FIG. 1B is a diagram of a component 120 in a field of view 122 inaccordance with an exemplary embodiment of the present invention.Component 120 can be encompassed by field of view 122 by rotating imagearea 104 about axis 124. If prism rotation system 108 is rotated in thedirection of the arrow in FIG. 1B, then first quadrant image data,second quadrant image data, third quadrant image data, and fourthquadrant image data can be generated that correspond to quadrants ofsemiconductor die 120. Likewise, areas outside of semiconductor die 120can also be encompassed, such that multiple semiconductor dies could beencompassed where the dies are small enough to fit within areas thatfall outside of semiconductor die 120. In this exemplary embodiment,system 100 can be used to perform inspection of all dies cut from awafer, or other suitable components.

FIG. 1C is a diagram of a lens apparatus 126 that is used to focus imagedata at viewing area 106. Light array 114 is shown disposed on prismrotation system 108, such that the lighting generated in image area 104remains uniform regardless of the angle of rotation of prism rotationsystem 108. As shown, rotating prism 102 reflects light from image area104, such that the field of view seen from viewing area 106 encompassesthe entire field view, whereas the image area seen from image area 104encompasses the focal point of lens apparatus 126.

FIG. 1D is a diagram of a light array 114 disposed about a prismrotation system 108 for rotating prism 102. As shown, light array 114can include a partial array of LED Lights or other suitable lights thatare used to maintain a constant lighting pattern regardless of the angleof orientation for prism rotation system 108 or rotating prism 102.

In operation, system 100 is used to perform inspection of one or morecomponents. System 100 allows pixel densities to be obtained by using arotating prism in a manner that allows an entire field of view to beinspected without moving the image data system or component. Likewise,multiple components can be inspected, such as dies cut from asemiconductor wafer, or other suitable inspections can be performed soas to avoid movement of an image data system or component.

FIG. 2 is a diagram of a system 200 for inspecting components inaccordance with an exemplary embodiment of the present invention. System200 includes prism rotation system 108, image data system 110, quadrantinspection system 112, prism rotation controller 202, image dataacquisition control 204, and quadrant data analysis system 206, each ofwhich can be implemented in hardware, software, or a suitablecombination of hardware and software, and which can be one or moresoftware systems operating on a general purpose processing platform.

Prism rotation controller 202 controls the speed of rotation for arotating prism 102 in conjunction with prism rotation system 108. In oneexemplary embodiment, prism rotation system 108 includes a support andassociated motors or other motive devices that are used to control anangle of rotation or speed of rotation of a rotating prism. Prismrotation controller 202 can adjust the speed of rotation so as tocorrespond to an image data system 110 frame generation rate or othersuitable factors.

Image data acquisition control 204 controls image data system 110 togenerate image data at a rate that corresponds to the rate of rotationof prism rotation system 108. In one exemplary embodiment, image datacan be generated for quadrants, or for other suitable areas, such thatimage data acquisition control 204 causes an image data system 110 tocapture image data presently in an area encompassed by viewing area 104.Image data acquisition control 204 receives prism rotation rate datafrom prism rotation controller 202, so as to ensure that the image datais generated in synchronization with the rotation of rotating prism 102.

Quadrant data analysis system 206 receives the image data generated byimage data system 110 and performs quadrant analysis on the data. In oneexemplary embodiment, quadrant data analysis system 206 can also performarea analysis for areas corresponding to one-third of the circular fieldof view, one-fifth of the circular field of view, or the suitable areas.Quadrant data analysis system 206 can identify features or items withina die or component, and can compensate for the degree or angle ofrotation from a reference point. In one exemplary embodiment, quadrantdata analysis system 206 can identify such features in a component imagedata set without rotating the image set, can compensate the image dataset for angular rotation, or can perform other suitable functions.

In operation, system 200 allows a component such as a semiconductor dieto be inspected where the level of detail that is required wouldotherwise require the die to be moved or the image data generationsystem to be moved to generate image data for the entire component.System 200 controls a rotating prism in a manner that image data for theentire component can be generated without moving the image datageneration system or the component, and further allows for angles ofrotation to be compensated for, either by rotating the image data,rotating the inspection frame, identifying components or features of theimage data regardless of the angle of orientation, or in other suitablemanners.

FIG. 3 is a diagram of system 300 for quadrant data analysis inaccordance with an exemplary embodiment of the present invention. System300 includes quadrant data analysis system 206 and die identificationsystem 302, feature identification system 304, and feature inspectionsystem 306, each of which can be implemented in hardware, software, orsuitable combination of hardware and software, and which can be one ormore software systems operating on a general purpose processingplatform.

Die identification system 302 identifies one or more die quadrants orother die features from image data. In one exemplary embodiment, asemiconductor die can be inspected such that the known dimensions,angular orientation, size of the die, and features on the die can beused to determine the angular orientation of the die in a set of imagedata. Die identification system 302 thus allows quadrants or othersections of the die to be identified based on die perimeter data orother suitable data.

Feature identification system 304 identifies one or more features withina set of image data. In one exemplary embodiment, feature identificationsystem 304 can be used in conjunction with die identification system302, such as where feature locations are known relative to die perimeterdata, die quadrant data, or other suitable data. Likewise, featureidentification system 304 can locate features in sets of image datawithout regard to the angular orientation of each quadrant or othersuitable data. In this exemplary embodiment, features havingpredetermined image parameters can be located using suitable image dataanalysis processes that do not require the angular orientation of thefeatures within the image data to be known.

Feature inspection system 306 receives feature image data from featureidentification system 304 and performs feature inspection, componentinspection, or other suitable inspections. In one exemplary embodiment,feature inspection system 306 can receive the image data directly andcan analyze the image data to locate defects, such as where the defectshave a known size, shape, color density, pixel brightnesscharacteristic, or suitable parameters that allow feature inspection tobe performed without previously identifying die perimeters, individualfeatures within the die, or other suitable elements. Likewise, featureinspection system 306 can receive component image data from featureidentification system 304, die identification system 302, or othersuitable systems, and can perform feature inspection based onpreviously-located die perimeters, components, or other suitable data.Likewise, other suitable processes can also or alternatively be used.

In operation, system 300 performs analysis and inspection of componentsand features using image data generated in conjunction with a rotatingprism. System 300 allows quadrants or other suitable sections ofcomponents, such as dies, to be inspected, such as by identifyingoutlines of the die or other components that are being inspected, byidentifying features within the die, by identifying damaged areas,either with or without adjusting for the angular orientation of thefeatures, or in other suitable manners.

FIG. 4 is a flowchart of a method 400 for performing an inspection usinga rotating prism in accordance with an exemplary embodiment of thepresent invention. Method 400 begins at 402 where image data isreceived. In one exemplary embodiment, the image data can be receivedthrough a prism or other suitable devices that convey image data from afirst area to a viewing area, such that rotation of the prism or otherdevice will allow a larger field of view to be encompassed at theviewing area than would be encompassed directly from the viewing areawith a predetermined pixel density and a predetermined pixel array size.The method then proceeds to 404.

At 404 component edges are identified. In one exemplary embodiment,image data analysis can first require identification of component edges,such as die edges or suitable data that is used to align the image data.Likewise, if component image data is not required, then the method canproceed directly to 406.

At 406 features within the component are identified. In one exemplaryembodiment, the features can be identified based on a predeterminedrelationship of the features to one or more edges, based on knownelements of the feature that allow the feature to be identified withoutpreviously identifying the component edges or the angular orientation ofthe component or section of the component being analyzed, or in othersuitable manners. Likewise, if identification of features within thecomponent is not required, such as where defect identification can beperformed based on known image data characteristics of defects, themethod can proceed directly to 408.

At 408 feature inspection is performed. In one exemplary embodiment, thefeatures can be inspected after correcting for angular rotation, afterlocating the features relative to an edge, or in other suitable manners.In another exemplary embodiment, feature inspection can be performed byprocessing the image data to locate defects based upon known image datacharacteristics of such defects. Likewise, a suitable combination ofprocesses can be used. The method then proceeds to 410.

At 410 it is determined whether the inspection is complete, such aswhether all quadrants of a die have been inspected, whether all featuresor components have been inspected, or whether additional image data isrequired. If the inspection is not complete then the method proceeds to412 where the prism or other device is rotated. In one exemplaryembodiment, the prism can be rotated through four quadrants so as togenerate an image of an entire semiconductor die. Likewise, other prismrotation angles can be used, all image data can be generated prior toperforming element inspection such that prism rotation is not required,or other suitable procedures can be used. The method then returns 402.

If it is determined at 410 that inspection is complete the methodproceeds to 414 where the inspection results are output. In oneexemplary embodiment, the inspection results can include a pass/failindicator as to whether or not the component should be accepted orrejected, such as control data that causes a failed component to markedor removed. Likewise, additional indicators can be provided, such asnotification data that additional operator review is required or othersuitable data. The method then proceeds to 416.

At 416 the next component is moved to the inspection position. Forexample, the components can be on a movable support such that the nextcomponent can be moved into the inspection position by moving thesupport. Likewise, the camera can be on a movable support such that thecamera is moved to the next component, or other suitable processes canbe used. The method then returns to 402.

In operation, method 400 is used to inspect components using a rotatingprism or other suitable devices that allow the viewing area to bechanged without moving the component, the camera, or otherwise takingactions that delay the inspection process. Method 400 can thus be usedto increase the inspection speed, such as where moving the camera orcomponent requires more time than rotation of a prism or other suitabledevices.

FIG. 5 is a flowchart of a method 500 for inspecting components inaccordance with an exemplary embodiment of the present invention. Method500 begins at 502 where the prism rotation speed or other suitabledevice rotation speed is set. In one exemplary embodiment, the prismrotation speed can be set based upon a maximum data generation rate ofan image data device, camera or other suitable devices. Likewise, wherethe rotation speed is fixed, the method can proceed directly to 504.

At 504 the camera image capture rate is set. In one exemplaryembodiment, the camera image capture rate can be adjusted based on therotation speed of the prism, can be calibrated or set to a predeterminedrate, or other suitable processes can be used to set the image capturerate. The method then proceeds to 506.

At 506 image data is received. The image data can include two or moresets of image data that encompass one or more components. In oneexemplary embodiment, a separate set of image data can be generated insequence for each of four quadrants of a single die as a rotating prismrotates through each of the quadrants, and can be received at 506. Inanother exemplary embodiment, where an entire semiconductor wafer hasbeen cut into dies and is being inspected, a suitable number of imagedata sets can be generated to cover all dies. Likewise, other suitableprocesses can be used. The method then proceeds to 508.

At 508, image data is analyzed. In one exemplary embodiment, image datais analyzed by first locating edges of a die or component, then bylocating features within the image data relative to the edges, and thenby inspecting each component individually. Likewise, the image data canbe analyzed by looking for predetermined defect identifiers in the imagedata sets, by identifying components based upon known component imagedata relationships without correcting for angular displacement, or inother suitable manners. The method then proceeds to 510.

At 510 it is determined whether the image data is acceptable. If it isdetermined at 510 that the image data is acceptable, the method proceedsto 512 where the next component is moved into position. In one exemplaryembodiment, a component support can be moved, the camera can be moved,or other suitable processes can be used. The method then returns to 506.

If it is determined at 510 that the image data is not acceptable, themethod proceeds to 514 where indication data is generated. In oneexemplary embodiment, the indication data can be a pass/fail indication,an indication that the component should be manually inspected, or othersuitable indication data. The method then proceeds to 512 where the nextcomponent is moved into place. Likewise, the questionable or defectivecomponent can be removed, such as by using a pick and place tool orother suitable devices.

In operation, method 500 allows component inspections to be performedusing a rotating prism or other suitable devices, so as to increase theinspection area for inspections performed at a given pixel densitywithout requiring the camera or component to be moved. Method 500further allows the angular displacement for such sets of image data tobe compensated for.

Although exemplary embodiments of a system and method of the presentinvention have been described in detail herein, those skilled in the artwill also recognize that various substitutions and modifications can bemade to the systems and methods without departing from the scope andspirit of the appended claims.

1. An inspection system comprising: a rotating prism having a first endand a second end, where the first end receives a first image area androtates about a center point so as to cover a field of view area that islarger than the first image area, and the second end remains centered onthe center point and provides the first image to a view area that hasconstant dimensions; and an image data system disposed at the second endof the rotating prism, the image data system generating image data asthe prism rotates so as to generate two or more sets of image data fromthe field of view area.
 2. The system of claim 1 further comprising asupport holding the rotating prism.
 3. The system of claim 2 wherein thesupport further comprises one or more lighting elements.
 4. The systemof claim 2 wherein the support further comprises a plurality of lightingelements disposed around a periphery of the support.
 5. The system ofclaim 1 further comprising a quadrant inspection system coupled to theimage data system, the quadrant inspection system receiving image datafrom one of four quadrants of the field of view area.
 6. The system ofclaim 1 further comprising a prism rotation controller coupled to therotating prism, the prism rotation controller setting the rotation speedof the prism.
 7. The system of claim 1 further comprising an image dataacquisition control coupled to the image data system, the image dataacquisition control setting an image capture rate.
 8. The system ofclaim 1 further comprising a quadrant data analysis system receiving theimage data and generating die quadrant image data.
 9. The system ofclaim 1 further comprising a die identification system receiving theimage data and generating die image data.
 10. The system of claim 1further comprising a component identification system receiving the imagedata and generating component image data.
 11. The system of claim 1further comprising a component inspection system receiving the imagedata and generating component pass/fail data.
 12. A method forinspection comprising: receiving image data of a first area from aprism; generating first area image data; rotating the prism; receivingimage data of a second area from the prism; generating second area imagedata.
 13. The method of claim 12 further comprising: receiving imagedata of a third area from the prism; generating third area image data;rotating the prism; receiving image data of a fourth area from theprism; generating fourth area image data; and wherein an item isinspected using the first area image data, the second area image data,the third area image data, and a fourth area image data.
 14. The methodof claim 13 wherein the item is a semiconductor die.
 15. The method ofclaim 13 wherein the first area image data corresponds to a firstquadrant of a semiconductor die, the second area image data correspondsto a second quadrant of the semiconductor die, the third area image datacorresponds to a third quadrant of the semiconductor die, and a fourtharea image data corresponds to a fourth quadrant of the semiconductordie.
 16. A method for inspecting a semiconductor die comprising:receiving image data of a first area from a prism; generating first areaimage data that includes a first section of the semiconductor die;rotating the prism; receiving image data of a second area from theprism; generating second area image data that includes a second sectionof the semiconductor die.
 17. The method of claim 16 wherein the firstsection and the second section are each quadrants of the semiconductordie, and the prism is further rotated to generate image data of all fourquadrants of the semiconductor die.
 18. The method of claim 16 furthercomprising rotating the second area image data to align with the firstarea image data.
 19. The method of claim 18 further comprisingeliminating overlapping sections of the image data.
 20. The method ofclaim 16 further comprising analyzing the second area image data basedon a predetermined angular relationship to the first area image data.